Identification and Integrative Bioinformatics Analysis of Common and Rare Mutations in the Patients with Transfusion Dependent HbE/b and b-thalassemia in Chittagong, Bangladesh

Abstract

Background: Thalassemia is an inherited blood disorder that affects hemoglobin’s structure and functions. Among several forms of this life-threatening disorder, HbE/β and β-thalassemia are most common in Bangladesh and worldwide as well. But the molecular and clinical data are not adequate regarding the underlying cause of this genetic disorder in Bangladesh. So, we aimed to identify the genetic mutations within β-globin gene (HBB) and to investigate the correlation of the mutations with HBB mRNA structure, gene transcription and hematological status among the patients with blood transfusion dependent HbE/β and β-thalassemia in Bangladesh. Methods: A total of 40 blood samples were collected from the patients with blood transfusion dependent HbE/β and β-thalassemia prior to taking their consent. Detection of mutations within HBB gene was carried out by polymerase chain reaction followed by Sanger DNA sequencing method. Identification and characterization of mutations along with their effects on HBB gene were analyzed by various bioinformatics approaches. In addition, complete blood count (CBC), and hemoglobin electrophoresis were done for hematological analysis. Results: c.92+5G>C, c.79G>A and c.9T>C genetic mutations were identified within the HBB gene, where c.92+5G>C was the most common mutation among the study patients. Mutations along with hematological status and putative transcription factor binding sites revealed that the severity of the disease depends upon the mutation type and its location in the HBB gene sequence. In addition, mRNA structure analysis showed that the identified mutations contribute to its structural diversity by altering folding mechanism that ultimately affects the stability and function of the HBB protein among the patients with blood transfusion dependent HbE/β and β-thalassemia. Conclusions: The study showed the underlying cause of HbE/β and β-thalassemia in genetic level by identifying rare and common mutations within HBB gene and their effects on with HBB gene transcription and mRNA structure. We hope study will contribute in designing effective molecular medicine and other therapeutics for the patients with HbE/β and β-thalassemia to improve their health condition. Bangladesh Medical Res Counc Bull 2022; 48(3): 180-188